1. Field
One embodiment of the invention relates to a projection display device that is suitably used for a color projector, especially, of a digital light processing (DLP) system, and a control method thereof.
2. Description of the Related Art
As widely known, a color projector of a DLP system allows light emitted from a white light source to sequentially pass through color segments of red (R), green (G), and blue (B) provided in a rotating color wheel and to be irradiated on a panel surface of a digital micromirror device (DMD).
In the DMD, optical images corresponding to R, G, and B light are formed by reflection of a number of micromirrors in synchronization with light sequentially irradiated on the panel surface after passing through the color segments of R, G, and B. Then, the optical images corresponding to R, G, and B light formed by the DMD are enlarged by a projection lens and projected on a screen. In this manner, color video display is carried out on the screen.
Here, in the color projector of the DLP system as described above, at present, there starts to be employed one that uses a color wheel, in which a white (W) segment that is an uncolored and transparent light transmission module is added to the color segments of R, G, and B, in order to improve luminous of projected images.
By using the color wheel added with the W segment, R, G, B, and W light is sequentially irradiated on the panel surface of the DMD in a time division manner. Then, when W light is irradiated, luminous can be increased by the light reflected to the projection lens by all micromirrors of the DMD.
In the color projector of the DLP system added with the W segment as described above, when images (hereinafter referred to as CG images) created by using a computer graphics (CG) technique, such as one for presentation or animations, is projected, there is a problem that degradation of color purity and degradation of saturation of colors cannot be avoided.
This problem occurs due to that luminous of a section with a light color and high luminous is optically increased, and a color of a colored object is recognized in high contrast with a white background in a scene where the colored object exists with the white background. Accordingly, due to nature of eyes of a human being, the colored section is seemed darkened in contrast. That is, due to visual influence of a white color, vividness of colors is sensed to be lost in contrast.
For the above reason, under present circumstances, a method of applying color correction processing for increasing lightness and saturation of colors is employed with respect to generation of the phenomenon described above, so as to prevent darkening of colors. However, the color correction processing as described above results in projection of unnatural images with colors that are too deep when the processing is applied to images (hereinafter referred to as natural images) obtained by shooting an optical image of an object receiving light irradiation from a light source.
Jpn. Pat. Appln. Publication No. 2008-185620 discloses a configuration where a projector receives input of image information showing an image and type information showing a type of the image from an image supply device. Then, a color mode for performing adjustment of colors is set in accordance with the type information, and a projected image is adjusted by a projection module in accordance with the set color mode.